The present invention relates to the production of baked corn-based snacks having a chip-like crispy texture and surface bubbles.
The production of traditional fried corn snacks generally involves a prolonged steeping step of about 10 to 20 hours. Whole kernels of corn are steeped in a hot lime solution to soften the outer hull and partially gelatinize the starch in the endosperm. The degree of gelatinization is generally about 10%. As disclosed in U.S. Pat. No. 4,645,679 to Lee, III, et al., both white and yellow corn of the dent type are added to a vat containing heated water and a proportionate amount of lime. The mixture is heated to the boiling point, the heat is cut off, and the contents of the vat are allowed to stand undisturbed for 10 to 20 hours. The lime loosens the pericarp from the endosperm so that water can reach the starch and so that the pericarp can be removed. If the pericarp remains, dough made from the steeped whole grains becomes excessively sticky. The corn kernels generally have a moisture content of at least about 50% by weight by the end of the steeping step. The heating and steeping steps result in hydration and partial hydrolysis of the corn hulls. The corn hulls are removed from the steeped kernels by washing. The washing may be performed with jets of water which also remove any remaining lime. The washed kernels are then ground in a stone mill into a dough containing about 50% or more moisture, known as masa.
As disclosed in U.S. Pat. No. 4,623,548 to Willard, the masa may be formed into thin pieces by extrusion, and the dough may be permitted to fall directly into hot cooking oil in a deep fat fryer. The oil replaces the water in the product resulting in a fried product having an undesirably high, for example at least 35% by weight, fat content and a hard and brittle texture. In another method, it is disclosed, a similar freshly ground masa is sheeted between rollers, cut into pieces, and baked to reduce the moisture content from about 35% to as low as about 20% before frying. According to U.S. Pat. No. 4,623,548 the dough should have a moisture content of about 50% for effective sheeting. Reducing the moisture content of the baked dough pieces reduces the fat content of the fried product to about 20% to 25%. However, according to U.S. Pat. No. 4,623,528 the fried pieces tend to have an uneven expansion, with large blistered areas and a hard, chewy texture. The same uneven structure, it is disclosed, is also found in the extruded masa-based snacks. Also, as disclosed in U.S. Pat. No. 4,645,679, the conventional process of producing corn chips has the disadvantages of producing chips which are gritty and do not easily melt in the mouth.
In the process of U.S. Pat. No. 4,645,679, hydrated corn having a moisture content of about 30% to about 40% is comminuted, and then admixed with a comminuted hydrated starch material selected from dehydrated potatoes, tapioca starch, corn starch, and mixtures thereof. However, the hydrated corn is still made by cooking raw corn kernels in water and lime, steeping until the hulls are softened, and washing the corn to remove the hulls. In a preferred embodiment the hydrated cut corn having a moisture content between about 30% and 40% is further hydrated by steeping it in water at a temperature of about 150xc2x0 F. to about 170xc2x0 F. for about 24 to about 48 hours to obtain a moisture content of about 60% to about 70%.
As disclosed in U.S. Pat. No. 4,623,548, dried masa flour has been used for the production of corn snacks and other Mexican food specialties, such as tortillas and taco shells. The dried masa flour is generally made by grinding the lime-treated corn and then dehydrating it to a stable form. A dried masa flour may then be rehydrated with water to form a dough for extrusion or sheeting. Whole corn kernels may be partially cooked, without lime treatment, that is without removing the outer hull, then dry-milled to obtain partially cooked, dry-milled whole corn flours. Dough for making a fried snack may be produced by mixing the whole corn flour with water. However, according to U.S. Pat. No. 4,623,548 fried snacks made from whole corn flours are hard and brittle and retain too much fat because of the low water absorption of the flours. In the process of U.S. Pat. No. 4,623,548, extruded expanded fried cereal-based snack products are produced using one or more raw or partially gelatinized cereal flours such as whole corn flour, masa flour, corn flour, barley flour, bulgur flour, cracked bulgur, oat flour, rye flakes, rye flour, and soy flour. The low water-absorbing component is admixed with a high water-absorbing component such as a pregelatinized cereal starch or flour or dehydrated potatoes. In addition, a starch component comprising one or more extraneously added ungelatinized starches is included. The three components, it is disclosed, are critical at the time of frying to obtain a controlled expansion into a well expanded, uniformly porous fried snack which differs from fried corn chips. The high water absorbing component, it is disclosed, retains the water in the formed dough piece as the temperature increases during frying. Sufficient water is therefore present at the gelatinization temperature to allow the other two components to absorb water when the dough reaches the gelatinization temperature and to cause formation of an expanded, uniformly porous fried snack.
U.S. Pat. Nos. 4,931,303 and 4,994,295 to Holm, et al. disclose that in the production of fabricated snack products having controlled surface bubbling, the dough sheet must have cohesive properties which permit the surface or surfaces of the dough or preform to stretch relatively uniformly when forming bubbles during frying. The highly cohesive, non-adhesive dough, it is disclosed, can be made by adjusting the quantity of free gelatinized starch, the degree of retrogradation of the starch (thereby affecting the water absorption of a given quantity of the starch) and the concentration of any starch-complexing emulsifiers present. In the Holm, et al. process, a dough may be formed comprising, e.g. potato solids or corn solids, raw or pre-gelatinized starches, modified starches, flavorings, oils, and the like. Dough pieces are subjected to case hardening by direct impingement gas-fired drying ovens, steam-heated conveyer dryers, infrared ovens or microwave ovens to promote surface bubbling during subsequent frying. It is disclosed that doughs containing less than about 30% moisture are generally too dry even after the Holm, et al. drying step to create adequate bubbles. In the Holm, et al. process, substantial moisture reduction of the dough is achieved by frying. During frying, the dough moisture content of about 30% to about 55% is reduced to obtain a fried product with a moisture content of about 1-2%. The product does not possess a light, crunchy texture.
German patent publication no. 4,137,161 (published May 13, 1993) to Reeg and corresponding Canadian patent publication no. 2082602 (published May 13, 1993) disclose the preparation of a maize dough for producing snack foods much as tortillas or taco shells by heating a mixture of ground corn, and water to 50-65xc2x0 C. which is just over the gelling point of the starch. Heating may be applied by friction from the mixing equipment or by passing steam into the mixture. The mixture is cooled while the starch is only partly gelled. The mixing of the ingredients to a homogeneous mass is preferably completed at room temperature. The mixture also contains sufficient calcium hydroxide to give a pH of 9-11.
Production of corn-based products including reduced fat, low-fat, and no-fat chips, taco shells, soft tortillas, and soft tacos is disclosed in U.S. Pat. No. 6,001,409 to Gimmler et al. The disclosed process uses ground corn products thereby eliminating the need for prolonged steeping times associated with the production of fried corn products conventionally made from whole corn kernels. Chip-like snacks having a crisp texture and chip-like appearance are produced from coherent, machinable, sheetable dough without using a frying step for substantial moisture reduction of the dough thereby resulting in products having low-fat content. The products possess a masa flavor and appearance which are comparable to those of products made using a traditional steeping process. However the product does not have surface bubbles and surrounding crisp, thin regions.
Baked hollow expanded snacks in the form of a figure such as an animal or vehicle disclosed in U.S. Pat. No. 4,752,493 to Moriki are produced from a farinaceous raw mixture. The raw mixture is prepared by mixing from 60-95 parts by weight of at least one low swelling-capacity farinaceous material and 40-5 parts by weight of at least one high swelling-capacity farinaceous material. The low swelling-capacity material may be a non-glutinous cereal such as wheat, rye, maize, non-glutinous rice, sago, sorghum, triticale, millet and beans, or starches separated from these sources. The high swelling-capacity material may be potato, taro, tapioca, arrowroot, sweet potato, glutinous rice, waxy corn, or starches derived from these sources having their cell walls broken. The farinaceous raw mixture is partly gelatinized prior to rolling into a smooth sheet by the addition of hot water or by the action of steam, so as to raise the temperature of the farinaceous raw mixture to 65xc2x0 C. to 90xc2x0 C. According to Moriki, upon baking, the starch in the surface of the dough pieces is gelatinized, thereby forming a skin having good gas-holding capacity and excellent stretchability. Water and volatile materials in the dough pieces push the skin outward upon heating, so that the dough pieces expand and are internally split into two layers or shells, forming a hollow space therebetween.
The filled crackers of U.S. Pat. No. 5,000,968 to Szwerc et al. are produced from a dough containing proteolytic enzymes. The enzymes hydrolyze proteins of the flour, which relaxes the dough and thereby permits a hollow center to be formed, rather than a cellular center, as the cracker expands under the influence of the leavening agent during baking. This, it is disclosed, strengthens the shell of the cracker and permits the cracker to be filled by means of an injection needle piercing the surface of the cracker.
The production of chip-like, starch-based snacks having a crispy texture and surface blisters from starch-based compositions which have little or no gluten, such as potato flour or corn flour, is disclosed in U.S. Pat. Nos. 4,873,093 and 4,834,996 to Fazzolare et al. and U.S. Pat. Nos. 5,429,834 and 5,500,240 to Addesso et al. Starch-based compositions which have little or no gluten, when mixed with water, do not form a dough that is cohesive at room temperature and continuously machinable or sheetable. Machinability of dough made from ingredients having little or no gluten may be improved by forming a dough under elevated temperature conditions, such as by steaming the ingredients, as disclosed in U.S. Pat. Nos. 4,873,093 and 4,834,996 to Fazzolare et al.
In the process of U.S. Pat. Nos. 5,429,834 and 5,500,240 to Addesso et al, use of a pregelatinized waxy starch provides for the production of cohesive, extensible, continuously machinable dough from starchy materials or ingredients having starch with no or low gluten. These machinable dough may be formed at room temperatures without the need for steaming or heat treatment to develop cohesiveness, extensibility, and machinability.
U.S. Pat. No. 4,560,569 to Ivers discloses that in the production of a dough-based fried food product, a processed starch in either gelatinized or ungelatinized form is frequently added when a low-starch flour or flake is employed. Water, it is disclosed, is required to soften the flour, and depending upon the protein content of the flour, to form a network of protein (gluten), which is the framework of the product. According to Ivers, starch, which is present in flours, is used as a binder and is required for the unleavened product to expand upon frying. Dough stickiness and hardness of the cooked product may be controlled by the addition of oil to the dough to control the extent of the protein framework. The dough is prepared by adjusting the ratios of components and the mixing time to allow it to sheet uniformly at the desired thickness without sticking or tearing. According to Ivers, addition of a small amount of a lecithin-in-water suspension to the formulation of the dough-based fried snack foods improves the transfer, sheeting and cutting, and significantly reduces clumping during frying, without the rapid buildup of free fatty acids and without significant darkening of frying oil, normally associated with the frying of foods containing lecithin.
U.S. Pat. No. 5,980,967 to Carey et al discloses production of wheat-based baked snacks containing a pregelatinized starch in the dough to create surface bubbles tends to result in a styrofoam-like or compressible texture, rather than a highly crisp, crunchy texture. Also, if the pregelatinized starch is not sufficiently hydrated prior to baking, bubbles created during baking tend to collapse.
In the present invention, corn-based, chip-like snacks having a crisp, crunchy chip-like texture and bubbles distributed over their surfaces are produced from cohesive, machinable, sheetable dough, without using a frying step for substantial moisture reduction of the dough, thereby resulting in products having low fat content. Surface bubbles comprising air pockets which extend from opposing surfaces are created and maintained during baking. The bubbles are maintained in portions of the baked dough, even though surrounding or adjacent portions of the dough have been dockered or punctured before baking. A pregelatinized waxy starch provides an extensible surface film prior to baking, which helps to temporarily trap moisture below the expandable film surface upon baking. Pregelatinized corn flour substantially improves corn flavor, and small amounts of baker""s bran provides the chip-like product with an appearance of roughness on the surface without deleteriously affecting bubble formation or retention. In addition, the machinable, continuously sheetable, corn-based dough may be produced at low temperatures. Sufficient hydration of the pregelatinized waxy starch and pregelatinized corn flour may be achieved by premixing them with hot water or by providing sufficient dough lay time for hydration to occur. The crispy, bubbled, corn-based snacks of the present invention include reduced fat, low-fat, and no-fat baked products, as well as full-fatted baked products.
The present invention provides a baked, corn-based, chip-like snack having surface bubbles comprising air pockets extending both above and below the substantially unleavened, adjacent portions of the snack. Dockering or piercing of the dough prior to baking results in localized unleavened or thinned areas and does not prevent the attainment of a plurality of discrete bubbles. Reduced fat, low-fat, and no-fat baked products, as well as full-fatted baked products, may be produced on a mass- production, continuous basis in accordance with the present invention. They are produced by admixing corn flour or corn meal, a film-forming pregelatinized waxy starch, a bubble-producing, flavor enhancing, pregelatinized corn flour, and a baker""s bran with water to hydrate the starch and flour materials and produce a machinable dough. Pregelatinized waxy maize starch is the preferred pregelatinized waxy starch. The pregelatinized corn flour is at least substantially completely pregelatinized corn flour. In addition to forming bubbles, it also improves and intensifies the corn flavor in the baked snack and enhances crispiness and crunchiness of the baked corn-based snacks. The corn flour or corn meal is preferably a partially gelatinized corn flour with a degree of gelatinization not exceeding about 60% and it is substantially different in functionality from the bubble-producing pregelatinized corn flour.
Use of the corn flour or corn meal, film-forming amounts of the pregelatinized waxy starch, and bubble-forming amounts of the pregelatinized corn flour provides for the production of a cohesive, non-sticky, extensible, continuously machinable dough. In embodiments of the invention, additional flavor ingredients, such as toasted corn germ, may be used along with the pregelatinized corn flour to enhance corn flavor of the final chip-like product. Also, baker""s bran may be used to provide the surface of the chip-like product with a rough appearance, characteristic of fried corn tortilla or fried corn chips.
The machinable dough of the present invention may be formed at room temperatures, without the need for steaming or heat treatment to develop cohesiveness, extensibility, and machinability. The dough may be machined using conventional cracker-dough technology, involving sheeting, dough-sheet lamination, dough-sheet thickness reduction, and cutting of the dough sheet into pieces.
In embodiments of the present invention, the dough pieces have a moisture content of from about 20% to about 50% by weight, preferably from about 25% by weight to about 45% by weight, more preferably from about 28% by weight to about 40% by weight. The moisture content of the dough pieces is reduced from these high levels to less than about 10% by weight, preferably less than about 5% by weight, most preferably less than about 3.5% by weight, by baking the pieces. This moisture reduction by baking results in baked pieces each having a plurality of surface bubbles distributed throughout their surfaces. The pieces may also include blisters interspersed with the bubbles. In embodiments of the present invention, frying may be performed subsequent to baking. The avoidance of frying for substantial moisture reduction of the dough pieces permits the attainment of crisp, chip-like snacks having a vegetable shortening or oil or fat content less than 20% by weight of the finished product.
In preferred embodiments of the present invention, a baked, corn-based, chip-like snack having surface bubbles and the texture and appearance of a corn chip, with the taste or flavor of tortilla products, may be produced without a leavened, mealy texture or a diluted, low intensity corn flavor.
The baked corn-based snacks may be produced by admixing: 1) corn flour or corn meal, which is only partially gelatinized, 2) pregelatinized waxy starch in an amount of from about 5% by weight to about 25% by weight, preferably from about 10% by weight to about 20% by weight, based upon the weight of the corn flour or corn meal, 3) at least substantially completely pregelatinized corn flour in an amount of from about 5% by weight to about 20% by weight, preferably from about 8% by weight to about 15% by weight, based upon the weight of the corn flour or corn meal, 4) from 0.1% by weight to about 10% by weight, preferably from about 0.5% by weight to about 5% by weight, of the baker""s bran, based upon the weight of the corn flour, and 5) water to hydrate said flours and starches and to form a machinable dough having a moisture content of preferably from about 28% by weight to about 40% by weight.
The dough may then be laminated upon itself, reduced in thickness to form a thin sheet, and then cut into pieces. The dough pieces are heated to reduce their moisture content and to obtain chip-like products having a bubbled appearance and a crisp texture and which make an audible crunching sound upon mastication.